General Alexander announced his retirement on October 16, 2013.[4] His retirement date was March 28, 2014.[5] In May 2014, General Alexander founded IronNet Cybersecurity, a private-sector cybersecurity firm based in Fulton, Maryland.[6]

Jessica L. Tozer sits down with NSA Director and CYCOM Commander General Keith Alexander to provide the NSA's point of view regarding its most criticized foreign intelligence and cybersecurity programs. (32:45min).

Additionally, Alexander held key staff assignments as Deputy Director and Operations Officer, Executive Officer, 522nd MI Battalion, 2nd Armored Division; G-2 for the 1st Armored Division both in Germany and during the Persian Gulf War, in Operation Desert Shield and Operation Desert Storm, in Saudi Arabia. He also served in Afghanistan on a peace keeping mission for the Army Deputy Chief of Staff for Intelligence.

Alexander headed the Army Intelligence and Security Command, where in 2001 he was in charge of 10,700 spies and eavesdroppers worldwide. In the words of James Bamford, who wrote his biography for Wired, "Alexander and the rest of the American intelligence community suffered a devastating defeat when they were surprised by the attacks on 9/11." Alexander's reaction was to order his intercept operators to begin to monitor the email and phone calls of American citizens who were unrelated to terrorist threats, including the personal calls of journalists.[1]

In 2003, he was named deputy chief of staff for intelligence for the U.S. Army. The 205th MI Brigade involved in the Abu Ghraib torture and prisoner abuse in Baghdad, Iraq was part of V Corps (US) and not under Alexander's command. Testifying to the Senate Armed Services Committee, Alexander called the abuse "totally reprehensible" and described the perpetrators as a "group of undisciplined MP soldiers".[11]Mary Louise Kelly, who interviewed him later for NPR, said that because he was "outside the chain of command that oversaw interrogations in Iraq", Alexander was able to survive with his "reputation intact".[12]

Alexander became a three-star general. In 2005, Donald Rumsfeld, secretary of defense, named him Director of the National Security Agency. There, according to Bamford, Alexander deceived the House Intelligence Committee when his agency was involved in NSA warrantless wiretapping.[1] Also during this period, Alexander oversaw the implementation of the Real Time Regional Gateway in Iraq, an NSA data collection program that consisted of gathering all electronic communication, storing it, and then searching and otherwise analyzing it. A former senior U.S. intelligence agent described Alexander's program: "Rather than look for a single needle in the haystack, his approach was, 'Let's collect the whole haystack. Collect it all, tag it, store it ... And whatever it is you want, you go searching for it."[16]

By 2008, the Regional Gateway was effective in providing information about Iraqi insurgents who had eluded less comprehensive techniques.[16] This "collect it all" strategy introduced by Keith Alexander is believed by Glenn Greenwald of The Guardian to be the model for the comprehensive world-wide mass archiving of communications which NSA had become engaged in by 2013.[17]

Alexander was confirmed by the United States Senate for appointment to the rank of general on May 7, 2010[19] and was officially promoted to that rank in a ceremony on May 21, 2010. General Alexander assumed command of United States Cyber Command in the same ceremony that made him a four-star general.[20]

He delivered the keynote address at Black Hat USA in July 2013. The organizers describe Alexander as an advocate of "battlefield visualization and 'data fusion' for more useful intelligence". He provided them with this quote:

As our dependence on information networks increases, it will take a team to eliminate vulnerabilities and counter the ever-growing threats to the network. We can succeed in securing it by building strong partnerships between and within the private and public sectors, encouraging information sharing and collaboration, and creating and leveraging the technology that affords us the opportunity to secure cyberspace ...[21]

Alexander gave the most comprehensive interview of his career, which spanned some 17,000 words, on 8 May 2014 to the Australian Financial Review journalist Christopher Joye, which was subsequently cited by Edward Snowden.[24] The full transcript, which covers NSA operations, Snowden, the metadata debates, encryption controversies, and Chinese and Russian spying, has been published online. On Snowden, Alexander told Joye: "I suspect Russian intelligence are driving what he does. Understand as well that they're only going to let him do those things that benefit Russia, or stand to help improve Snowden's credibility".[25]Wired magazine said the AFR interview with Alexander showed he was defending the stock-piling of zero-days while The Wall Street Journal and other media focused on Alexander's claims about Snowden working for Russian intelligence.[26][27] In July 2012, in response to a question from Jeff Moss, founder of the DEF CON hacker convention, "... does the NSA really keep a file on everyone?," Alexander replied, "No, we don't. Absolutely no. And anybody who would tell you that we're keeping files or dossiers on the American people knows that's not true."[28]

In March 2012, in response to questions from Representative Hank Johnson during a United States Congress hearing about allegations made by former NSA officials that the NSA engages in collection of voice and digital information of U.S. citizens, Alexander said that, despite the allegations of "James Bashford" [sic] in Wired magazine, the NSA does not collect that data.[29]

On July 9, 2012, when asked by a member of the press if a large data center in Utah was used to store data on American citizens, Alexander stated, "No. While I can't go into all the details on the Utah data center, we don't hold data on U.S. citizens."[30]

At DEF CON 2012, Alexander was the keynote speaker; during the question and answers session, in response to the question "Does the NSA really keep a file on everyone, and if so, how can I see mine?" Alexander replied "Our job is foreign intelligence" and that "Those who would want to weave the story that we have millions or hundreds of millions of dossiers on people, is absolutely false ... From my perspective, this is absolute nonsense."[29]

On June 6, 2013, the day after Snowden's revelations, then-Director of National Intelligence James Clapper released a statement admitting the NSA collects telephony metadata on millions of Americans telephone calls.[31] This metadata information included originating and terminating telephone number, telephone calling card number, IMEI number, time and duration of phone calls.[32]

Andy Greenberg of Forbes said that NSA officials, including Alexander, in the years 2012 and 2013 "publicly denied—often with carefully hedged words—participating in the kind of snooping on Americans that has since become nearly undeniable."[29] In September 2013, Alexander was asked by Senator Mark Udall if it is the goal of the NSA to "collect the phone records of all Americans", to which Alexander replied:

Yes, I believe it is in the nation's best interest to put all the phone records into a lockbox that we could search.

In May 2014, after his retirement from NSA, General Alexander founded IronNet Cybersecurity.[6] IronNet provides cybersecurity coverage for private-sector companies using its IronDefense program and a team of cybersecurity analysts and experts. The company is headquartered in Fulton, Maryland with offices in Frederick, Maryland, McLean, Virginia, and New York City. In October 2015, IronNet received $32.5 million in funding from Trident Capital Cybersecurity (now ForgePoint Capital) and Kleiner Perkins Caufield & Byers in a Series A investment.[34][6] In May 2018, IronNet raised an additional $78 Million in a round led by C5 Capital alongside existing investors ForgePoint Capital and Kleiner Perkins Caufield & Byers.[35] General Alexander maintains his role as CEO of IronNet today.